In 1785, Luigi Valadier created a spectacular mounting for this no less exceptional cameo, carved in the 1st century AD with the likeness of the Roman emperor Augustus. Designed as a portable item of imperial propaganda, the bust is one of numerous portraits executed during Augustus's reign (27 BC-AD 14), in pietre dure, marble, or in cameo form. The 18th-century mounting incorporates a number of antique elements: the eagle's head, phalerae, and breastplate.

A portrait of the emperor Augustus

The cameo features an agate portrait bust of the emperor Augustus, dressed in the paludamentum or purple cloak of the commander-in-chief of the Roman army. Stylistically, the bust belongs to one of the principal types of carved portrait of Augustus (datable to c. 20 BC); it was probably carved during his lifetime at the beginning of the 1st century AD, and closely resembles a statue discovered at Livia's villa in Prima Porta. The modeling of the emperor's face conveys the same sense of energy; both works also include a similar hair arrangement, notably the distinctive part and cleft in the bangs over the left eye and temple.

The dissemination of imperial likenesses

The exact purpose of the cameo is unclear. Unusually, the portrait is carved into a spherical piece of stone, and is hence neither strictly a cameo relief, nor a fully three-dimensional piece. It may have been intended as a decorative handle at the top of a shaft, possibly a scepter. The work is one of a number of surviving portraits of Augustus, including marble effigies and more prestigious pieces carved in pietre dure, intaglio, or cameo. The last of these were easily transported throughout the provinces of the Empire, due to their small size, and were used as items of imperial propaganda. They were thus generally very finely carved. A cameo portrait of Augustus in the medals collection at the Bibliothèque Nationale in Paris is another excellent example.

The mounting by Luigi Valadier

In 1785, the Italian goldsmith Luigi Valadier was commissioned to create a sumptuous mounting for the present cameo, then in the Vatican collection (since 1741). The mounting is an original work, incorporating newly created figures along with fragments of Roman art from the papal collections. Six gilded-bronze figures of slaves are seated around a hexagonal base in red marble, separated by antique phalerae in chalcedony, representing childlike masks (some carved in minute detail, others more schematic). An armed trophy above the figures is composed of fragments dating from the 1st century BC or the 1st century AD: phalerae and an eagle's head in agate, a breast-plate in rock crystal, and a sard vase fragment. The trophy is surmounted by a gilded-bronze eagle with unfurled wings, supporting a laurel wreath in enameled gold, framing the cameo of Augustus. Valadier seems to have been inspired by the marble monument to Claudius (AD 41-54) now in the Museo del Prado, Madrid, which also features an imperial portrait supported by an eagle and an armed trophy. Valadier's work was dismantled in the late 19th or early 20th century and reassembled in 1988-90.